1. Field of the Invention
This invention relates generally to manually propelled bicycles, and more specifically to exercise, recreation, and transport bicycles that include a pedal and chain mechanism having a teardrop motion that allows for stair-stepping type exercise propulsion during transport of the bicycle.
2. Description of Related Art
The use of bicycles for exercise, recreation, and transport and other activities such as racing is well known in the prior art. On a conventional bicycle the operator traditionally sits on a seat and the pedal motion is essential circular. The use of chain, multiple gears and clutch mechanisms in conjunction with the pedal and sprocket are well known to provide for different gear ratios between the pedal sprocket and the rear wheel and a clutch mechanism that allows the bicycle to continue to coast forward when the pedals are stopped at any position.
One of the problems with a conventional bicycle from an ergonomic standpoint is that the operator is in a seated position, performing mechanical work in a relatively stressful positionxe2x80x94bent forward at the waist, relying predominantly upon his/her quadricep muscles for propulsion and exercise. By placing the body in an upright position, the most efficient body position is achieved, utilizing a full complement of lower extremity muscles.
Stair-stepping type exercise is also known in the art. The objective is to decrease stress on the spine, joints, and lower extremities and to simulate walking upstairs for increased aerobic value. It is the intent of this invention to effectively combine the stair-stepping activity with recreational riding and transport by a bicycle.
There are devices shown in the prior art that attempt to provide a minimum form of exercise using pedals in an up and down motion. U.S. Pat. No. 5,192,089 issued Mar. 9, 1993, to Taylor shows a pedal operated scooter that includes cables, pulleys, and tension devices. The device is complex having a propulsion unit including multiple opposing sprockets and cables. The pedal mechanism is pivotal centrally.
U.S. Pat. No. 5,368,321, issued Nov. 29, 1994 to Berman et al., shows a dual footboard low profile exercise cycle. This device employs a chain and sprocket mechanism that is overly complex, expensive and does not provide a teardrop motion. It is believed that the teardrop motion provides better exercise results as a more natural movement for a person in the upright stair-step action. No related art presents a coupled oscillating teardrop motion.
U.S. Pat. No. 5,520,401, issued May 28, 1996 to Mohseni, shows a step drive cycle, having a conventional bicycle type configuration with a very complex proportioned system utilizing a plurality of belts and pulleys not in the present invention.
The present invention overcomes the problems in the prior art by providing a bicycle frame profile specially suited to a teardrop and stair-stepping type motion with a noncomplex propulsion system having conventional sprockets, multi-gear and clutch mechanism configured to provide for safe, stable, and efficient stair-stepping motion. The frame configuration insures that each pedal achieves a horizontal position upon a complete and full downstroke of each foot pedal. The invention also includes a spring-loaded, cable-controlled bike stand encased within the protective housing which allows the unit to be stationary in an upright position when not in use.
A bicycle for providing stair-stepping exercise motion, recreation, and mode of transport comprising a frame that includes a unique triangular rear portion, a pair of wheels, one for the front, one for the back, a chain driven, teardrop-shaped propulsion system, left and right pedals having multiple positions between a horizontal and angular vertical upon which the operator rides, adjustable handle bars for steering, and a safety housing for covering the propulsion and wheel sprockets, chains braking mechanism, and bike stand.
The frame is constructed of a tubular, light weight, strong material such as steel or aluminum, and includes a unibody designed center portion, a triangular rear frame portion which consists of a center vertical strut, two upper rear frame connectors, and two lower rear frame connectors which connect the rear wheel and the propulsion sprocket to the frame, and a forward angled frame portion that includes dual columns for retaining and attaching the front wheel of the bicycle.
The forward frame portion also includes a slightly angled yet substantially vertical tubular section to receive an adjustable height handlebar for steering. This forward frame portion may be hinged to provide for adjustable angular settings to accommodate various size operators. The steering mechanism is substantially conventional, as on a conventional bicycle in which the handlebars are connected to a pivotal fork that allows turning of the front wheel while the frame remain rigid. The forward vertical tubular section of the bicycle frame is angled upwardly to connect to or receive the handlebar support.
The rear portion of the frame includes on each side a left and right upper and lower rear frame connector that joins the rear wheel to the frame, essentially supporting the rear wheel in a fork to a main vertical strut elevated from the base of the frame. Specifically, the upper rear frame connector is superiorly angulated approximately 30-35 degrees from the center of the rear wheel, while the lower rear frame connector is inferiorly angulated from the center of the rear wheel to meet the posterior aspect of the intersection of the main vertical strut and center portion of the unibody frame. A superior sprocket is mounted on the superior aspect of the vertical strut at the intersection of the upper rear frame connector and the vertical strut and is connected by a conventional bicycle chain to an inferior sprocket on the rear wheel which can contain multiple gears, a clutch mechanism and a conventional bicycle propulsion unit at the rear wheel. The lower rear frame connector is angled such that the entire frame, especially through its middle portion, is completely horizontal to the riding surface and is about 6 to 8 inches off the ground. Preferably the rear wheel will be larger in diameter than the front wheel to allow adequate ground clearance of the most inferior aspect of the chain mechanism and protective housing cover, to allow adequate ground clearance of the down stroke foot pedal especially at the rear of each foot pedal, with its lowest position being horizontal to the earth and parallel to the unibody frame, to lessen the amount of work and effort required of the operator to achieve the desired speed and performance, to maintain a fairly modest standard length of the bicycle frame, thereby providing a shallower pitch and angulation of the foot pedals, thus ensuring stability and safer operation. The preferred ratio of rear to front wheel diameters is about 2:1. There appears to be no mechanical or structural advantage achieved by utilizing equal wheel dimensions, however, a step-cycle would function using equal wheel dimensions.
A pair of elongated left and right pedals are pivotally and moveably attached at the front ends to projections extending laterally from the frame on each side. The forward connection of each pedal includes an elliptical slot that fits into the frame projections that permits front and backward motions and pivotal motion of the pedal at the front portion of the pedal.
The superior propulsion sprocket mounted on the superior aspect of the main vertical strut includes two sprocket arms extending and rigidly affixed to the sprocket in opposite 180-degree directions that have connectors that connect to the rear end portion of each pedal which permit rotational movement of the rear portion of the pedal.
In its lowest downstroke position, one pedal would be horizontal to the frame and the ground, and the opposite pedal will be in its most angulated/pitched position while in its highest upstroke position.
A protective housing is used to encase the superior and inferior rear sprocket propulsion system, the rear braking mechanism, chain, and bike stand of the rear wheel. This housing is made of a bi-fold, durable plastic which is designed to prevent any interaction between these components and the operator or the operator""s clothing. This bi-fold design is held together with 4-5 easy turn screws which allows for easy access to these components.
Within the protective housing is also a spring-loaded, cable-controlled, moveable, rotatable, rigid bar that has two positions, up or down, that acts as a bike stand to allow support of the bicycle in an upright position when it is not being operated. The bike stand is stored within the protective housing when not in use. The cable-controlled bike stand utilizes two springs, one large and one small. The large spring with stronger tension is used to set the bike stand into the lowered xe2x80x9creleasedxe2x80x9d position. This spring attaches the bike stand to the fixed side of the rear wheel protective bi-fold cover. The small spring with lighter tension is connected to a stopper/latch which holds the bike stand in the upright xe2x80x9clockedxe2x80x9d position. A first cable end will connect to the small spring loaded stopper/latch, while a second cable end is connected to a handlebar lever accessible to the rider. By simply tightening the handlebar lever, the small spring connected to the stopper latch will compress and shorten, releasing the larger spring and bike stand into the lowered xe2x80x9creleasedxe2x80x9d position.
The operator can stand on each pedal and apply downward pressure on one of the pedals to begin propulsion of the bicycle, thereafter alternating this stair-step action between pedals. This continued stair-stepping motion can be continuously applied or the operator can stop the stair-step motion and the bicycle will continue to coast because the sprocket clutch allows free wheeling of the bicycle in a forward direction when the pedals are not being operated. During operation of the stair-stepping motion on the propulsion unit, each pedal can move backwards and forwards at the forward portion of the pedal and circularly at the rear portion of the pedal providing an overall natural teardrop exercise motion. The low angled frame of the bicycle is very stable and reduces the center of gravity. The triangular rear frame portion includes one main vertical strut, two lower rear frame connectors, and two upper rear frame connectors, which are angled at approximately 30 to 35 degrees and provide the proper orientation and range of motion of the pedals during exercising while providing a noncomplex propulsion unit using conventional bicycle sprockets and a multiple gear mechanism.
Conventional type brake pads are uniquely positioned on the two lower rear frame connectors, angled superiorly and obliquely. These brake pads are covered by the protective housing. These rear brake pads create drag on the bicycle rear tire from a hand actuated hinged handle mounted on the handlebars to which the brake cables are connected. Front brake pads will be utilized in the same conventional manner on the front wheel.
It is the object of this invention to provide an improved bicycle for exercise, recreation, and transport which uses a teardrop stair-stepping motion to propel the bicycle.
Yet another object of this invention is to provide an improved bicycle construction utilizing a substantially conventional sprocket and chain technology in a noncomplex way to provide a stable platform for a teardrop stair-stepping exercise and mode of transportation.
Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
In accordance with these and other objects, which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.